Embodiments of the inventive concepts described herein relate to a receiver for performing signal processing for energy charging and data decoding in a wireless communication environment for simultaneously supporting wireless energy charging and data transfer and a signal processing method thereof, and more particularly, relate to technologies for simultaneously supporting signal processing for energy charging of signals received at a receiver and signal processing for data decoding if performing wireless energy charging and data transfer using radio frequency (RF) signals.
In a next generation mobile communication system, a transmitter uses RF signals as a medium for directly transferring energy as well as transferring data. A receiver supports wireless energy transfer technologies of supporting energy harvesting of receiving energy transferred over wireless channels and recharging a battery of a limited capacity. The wireless energy transfer technologies address a problem where a supplied power is limited and where the cost of replacing a battery is high, facilitate a continuous operation of the receiver, and support green communication through efficient energy recycling of radio wave resources thoughtlessly wasted.
However, a general signal processing method for receiving data transferred from the transmitter at the receiver and for data decoding at the receiver is unsuitable for wireless energy transfer. In other words, if signal processing is performed with respect to a signal for simultaneously performing wireless energy charging and data transfer using a signal processing method used for data decoding, there is low energy transfer efficiency. Similarly, since it is impossible to transfer data using a phase of an RF signal in a signal processing method of the receiver for maximum wireless energy transfer, it is difficult to decode a large amount of data.
For example, if the whole signal transmitted from the transmitter is used for energy charging and if Bluetooth communication is used as communication for data transfer, there is a need for setting an optimal parameter for charging. If a receiver is charged using magnetic charging, it has a very limited charging distance within dozens of centimeters or one meter and has a low data rate. In this case, a charging distance may be broadened using an RF, but charging efficiency is more reduced in the RF as a distance between a transmitter and a receiver is distant.
Thus, there is a need for signal processing technologies of simultaneously considering signal processing of a receiver for wireless energy transfer and signal processing of the receiver for data transfer upon RF-based wireless energy charging.
FIG. 1 is a block diagram illustrating a configuration of a receiver for simultaneously performing energy recharging and data decoding using time division.
Referring to FIG. 1, a transmitter (not shown) such as a base station (BS) may transmit a transmit signal for energy recharging and data decoding to a receiver 100. The receiver 100 may receive the signal transmitted from the transmitter. In this case, the receiver 100 may divide a time into a time ρ for energy recharging and a time 1−ρ for data decoding.
A signal received during the time ρ from the transmitter, that is, an RF signal may be rectified by passing through a rectifier 120. As such, as the signal passes through the rectifier 120, energy may be harvested. An energy recharging unit 130 may recharge a battery of the receiver 100 which is user equipment (UE) using the harvested energy.
The data decoding unit 110 may decode data based on a signal received during the time 1−ρ from the transmitter.
The time division method described with reference to FIG. 1 may perform only signal processing for energy recharging without performing data decoding during the time ρ. The time division method may perform only signal processing for data decoding without performing signal processing for energy recharging during the time 1−ρ.
FIG. 2 is a block diagram illustrating a configuration of a receiver for simultaneously performing energy recharging and data decoding using power split.
Referring to FIG. 2, a transmitter (not shown) such as a BS may transmit a transmit signal for energy recharging and data decoding to a receiver 200. The receiver 200 may receive the signal transmitted from the transmitter. In this case, the receiver 200 may divide a signal received from the transmitter, that is, an RF signal into a signal having energy of a constant rate ρ and a signal having energy of the remaining rate 1−ρ.
A rectifier 220 may harvest energy by passing only the signal of the rate ρ in the RF signal. An energy recharging unit 230 may recharge a battery (not shown) of the receiver 200 using the harvested energy.
A data decoder 210 may perform data decoding using only the signal of the rate 1−ρ. In other words, the power split method may split a power of the received signal into the rate ρ and the rate 1−ρ, may use the signal having the energy as much as the rate ρ for only signal processing for energy recharging, and may use the signal having the energy as much as the rate 1−ρ for only signal processing for data decoding.
The time division method and the power split method described with reference to FIGS. 1 and 2 may support simultaneous energy and data transfer through an operation of dividing an RF signal received from the transmitter into two parts and using the divided two parts to suit different purposes (e.g., energy recharging and data decoding). In this case, as the signal is divided into two parts and the two parts are processed based on purposes, only part of a received signal rather than the whole received signal may be used for energy recharging, and only the remaining signal may be used for data decoding. Thus, data decoding efficiency may be reduced in view of energy recharging, and energy recharging efficiency may be decreased in view of data decoding. In other words, the receiver may have low transfer efficiency.
FIG. 3 is a block diagram illustrating a configuration of a receiver for performing energy recharging and data decoding using the whole RF signal received from a transmitter.
Referring to FIG. 3, a transmitter (not shown) such as a BS may transmit a transmit signal for energy recharging and data decoding to a receiver 300.
A rectifier 310 may first rectify the whole RF signal which is a signal received from the transmitter for energy recharging. Part of a signal passing through the rectifier 310 may be transmitted as an input of an energy recharging unit 330 for energy recharging, and the remaining signal except for the part in the signal passing through the rectifier 310 may be transmitted as an input of a data decoder 320 for data decoding.
For example, the data decoder 320 may receive a signal as much as a rate 1−ρ in the signal passing through the rectifier 310 and may decode data. As such, the receiver 300 may convert the signal received from the transmitter into a baseband signal by passing the whole received signal through the rectifier 310 and performing data decoding with respect to the signal passing through the rectifier 310. The receiver 300 may perform analog-to-digital conversion (ADC) of the baseband signal, thus saving consumed energy.
In this case, while the received signal passes through the rectifier 310, phase information of original data included in the received signal may be changed or lost. In other words, as the whole received signal passes through the rectifier 310, a phase of the whole received signal may be lost. As a result, decoding efficiency of a large amount of data may be reduced due to the phase loss.
Thus, there is a need for technologies of supporting an amount of charged energy user equipment (UE) (e.g., a smartphone, a tablet personal computer (PC), or the like) which is a receiver wants through an operation of rectifying a received signal and supplementing a phase information loss of data due to passing through a rectifier.
Korean Patent Laid-open Publication No. 10-2009-0019974 relates to a wireless charging system and a control method thereof and describes technologies of transmitting a charging signal based on battery state information, receiving a charging signal, and charging a battery. In other words, Korean Patent Laid-open Publication No. 10-2009-0019974 describes technologies of automatically performing a charging function based on the remaining capacity of a battery of a portable device having a wireless charging function and a data communication function.